1. Field of the Invention
The present invention relates to a semiconductor die package, and more particularly to an encapsulated semiconductor die package that can keep from bending.
2. Description of Related Art
With reference to FIG. 2, a conventional semiconductor die package in accordance with the prior art comprises a lead frame (21), a die (20) and an encapsulant (23). A passage (211) is defined in the middle portion of the lead frame (21), and multiple internal leads (not shown) are mounted on the lead frame (12) around the passage (211). Multiple external leads (112) are mounted around the lead frame (21) and extend outward from the encapsulant (23). In practice, because the I/O nodes (not shown) of the die (20) are arranged in the middle portion of the die (20), the die (20) is usually mounted on the bottom of the lead frame (Lead on Chip, LOC) by means of an adhesive layer (24). A bonding wire (22) is electrically connected between each internal lead (not shown) of the lead frame (21) and each corresponding I/O node (not shown) of the die (20). The encapsulant (23) is used to enclose the lead frame (21), die (20) and all of the bonding wires (22) to protect the encapsulated components. In the prior art, the distance (e) between the lead frame (21) and outside face of the encapsulant (23) is equal to the distance (f) between the lead frame (21) and the other outside face of the encapsulant (23).
However, the distance (g) between the die (20) and the outside bottom face of the encapsulant (23) in the conventional semiconductor die package is smaller than the distance (e) between the lead frame (21) and the top face of the encapsulant (23). The surface of the package easily bends upward in the packaging process due to the uneven curing speed between different parts of the encapsulant (23). Consequently the external leads (112) will not be in the same plane due to the deformation of the package.
With reference to FIG. 3, another conventional semiconductor die package was provided to solve the deformation problem. The distance (h) between the lead frame and the top outside face of the encapsulant (33) of the conventional semiconductor die package is formed to be substantially equal to the distance (i) between the die (30) and the bottom outside face of he encapsulant (33).
However, the distance (j) between the lead frame (33) and the bottom outside face of the encapsulant (33) of the conventional semiconductor die packaged device is about three times the distance (h) between the lead frame (31) and the top outside face of the encapsulant (33). Therefore, the bottom surface of the package easily bends downward in the packaging process because the curing speed of the lower encapsulant (33) portion is much slower than that of the upper encapsulant (33) portion.
To overcome the shortcomings, the present invention tends to provide an improved semiconductor die package to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide an improved semiconductor die package having a lead frame, a die attached to the lead frame and an encapsulant enclosing the lead frame and the die. The distance between the top outside face of the encapsulant and the frame is substantially equal to the distance between a bottom outside face of the encapsulant and the die, and the distance between the bottom outside face of the encapsulant and the lead frame is substantially two and half times the distance between the top outside face of encapsulant and the lead frame. This can effectively reduce the deformation of the encapsulant.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.